error = False

try:
    num1 = float(input("请输入第一个数字:"))
except:
    error = True
    print("请输入正确的数字")

try:
    num2 = float(input("请输入第二个数字:"))
except:
    error = True
    print("第二个数字输入错误")

try:
    op = input("请输入(+,-,*,/)")
except:
    error = True
    print("操作符输入错误")

if error:
    print("Something wrong")
else:
    if op == "+":
        result = num1 + num2
    elif op == "-":
        result = num1 - num2
    elif op == "*":
        result = num1 * num2
    elif op == "/":
        result = num1 / num2
    else:
        result = "错误的运算符"
    print("result=", result)

